A review of the available literature on neonatal limitation has revealed that there is strong evidence for the existence of a tongue protrusion effect. That is, after demonstration of tongue protrusion by a model neonates tend to increases their rate of tongue protrusion. Every study that used total demonstration time of 1 minute or more obtained the effect. The project is designed to explore three explanations of the tongue protrusion effect. The most obvious but at the same time the most theoretically demanding explanation is that the effect represents a rudimentary form of imitation, implying that neonates are able to match the visual image that they obtain when they see the model's tongue with the kinesthetic sensation that they experience when they themselves produce the gesture. The second explanation is that the attentional responses elicited by the demonstration compete with the normal spontaneous production of tongue protrusion. According to this hypothesis, the "damned up" tongue protrusions are released in the response period following demonstration. The third explanation is that seeing the demonstration of tongue protrusion is arousing to the neonate, and arousal increases the rate of production of tongue protrusions. A series of experiments with subjects ranging in age from newborn to 12 weeks is proposed to test these explanations. In the experiments infants will be exposed to demonstration of tongue protrusion and mouth opening as well as to nongesturing models, and to stimulus conditions that elicit attention or arousal without modeling. The infants will be videotaped throughout testing. A wide range of infant responses will be code and analyzed, including: tongue protrusion, mouth opening, limb movement, and direction of looking. Heartrate, as a measure of arousal, will be monitored. The broad aim of this research is to help understand the nature and level of early human capacities.